Honeywell S7800A1142 Keyboard Display Module
The Honeywell S7800A1142, also cataloged as the S7800A Keyboard Display Module, operates as a dedicated hardware component for localized diagnostic readout, parameter configuration, and status monitoring within 7800 Series burner control system networks. It establishes direct serial communications with the main burner control module to display operational timing, flame signal strength, lockout sequence cause data, and system diagnostic codes in real time.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | S7800A1142 (S7800A) |
| Brand | Honeywell |
| Origin | USA |
| Weight | 0.32 kg (Shipping Weight: 0.80 kg) |
| Dimensions | 127 mm x 73 mm x 22 mm |
| Operating Temp | -40 to 60 deg C |
| Power Consumption | 13 VDC @ 100 mA max (supplied by 7800 Series module) |
| Module Type | Keyboard Display Module (KDM) |
| Display Technology | 2-line x 20-character vacuum fluorescent display (VFD) |
| Keypad Interface | 5-button membrane keypad (Scroll, Mode, Reset, Change, Enter) |
| Enclosure Protection | NEMA 1 / IP40 |
| Subsystem Compatibility | Honeywell 7800 Series Relay Modules |
4-20 mA HART Loop Protocol Integration and Channel-to-Channel Isolation
While functioning as a local human-machine interface for flame safeguard controllers, the S7800A1142 operates across isolated low-voltage serial data channels. Internal optocouplers deliver galvanic isolation between the local display electronics and the high-voltage ac field terminal wiring on the host 7800 Series relay module. This prevents high-voltage ignition surges, switching noise, and common-mode transients from corrupting micro-controller memory registers. When installed in burner control cabinets alongside process control instrumentation utilizing 4-20 mA HART loop protocol communications or cold junction compensation (CJC) reference junctions for temperature loop control, the module maintains electromagnetic immunity and preserves digital data communication stability.
Frequently Asked Questions
Q: Can the S7800A1142 keyboard display module be removed or plugged in while the host relay module is powered?
A: Yes. The module supports hot-plugging directly into the front card slot of an energized 7800 Series relay module without causing interruption to active flame monitoring operations or fault reset sequences.
Q: How far can the S7800A1142 be remote-mounted from the main burner controller module?
A: Remote mounting is supported up to a maximum physical cable length of 1000 feet (305 meters) using a dedicated remote mounting kit with shielded twisted-pair conductors.
Field Installation Guidelines
- Power down primary ac line power to the 7800 Series burner control enclosure if installing an optional flush-mount door frame.
- Align the rear serial connector pins of the S7800A1142 with the front mating header socket on the 7800 Series relay module.
- Press the keyboard display module firmly into place until the top and bottom plastic locking tabs engage securely.
- For remote door-mounting applications, ground the serial cable shield drain wire at the panel functional earth (FE) terminal block only.
- Apply main power to the relay module and verify that the display initializes, showing system status and flame signal strength in millivolts.
Honeywell S7800A1142 Keyboard Display Module
Honeywell S7800A1142 Keyboard Display Module
The Honeywell S7800A1142, also cataloged as the S7800A Keyboard Display Module, operates as a dedicated hardware component for localized diagnostic readout, parameter configuration, and status monitoring within 7800 Series burner control system networks. It establishes direct serial communications with the main burner control module to display operational timing, flame signal strength, lockout sequence cause data, and system diagnostic codes in real time.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | S7800A1142 (S7800A) |
| Brand | Honeywell |
| Origin | USA |
| Weight | 0.32 kg (Shipping Weight: 0.80 kg) |
| Dimensions | 127 mm x 73 mm x 22 mm |
| Operating Temp | -40 to 60 deg C |
| Power Consumption | 13 VDC @ 100 mA max (supplied by 7800 Series module) |
| Module Type | Keyboard Display Module (KDM) |
| Display Technology | 2-line x 20-character vacuum fluorescent display (VFD) |
| Keypad Interface | 5-button membrane keypad (Scroll, Mode, Reset, Change, Enter) |
| Enclosure Protection | NEMA 1 / IP40 |
| Subsystem Compatibility | Honeywell 7800 Series Relay Modules |
4-20 mA HART Loop Protocol Integration and Channel-to-Channel Isolation
While functioning as a local human-machine interface for flame safeguard controllers, the S7800A1142 operates across isolated low-voltage serial data channels. Internal optocouplers deliver galvanic isolation between the local display electronics and the high-voltage ac field terminal wiring on the host 7800 Series relay module. This prevents high-voltage ignition surges, switching noise, and common-mode transients from corrupting micro-controller memory registers. When installed in burner control cabinets alongside process control instrumentation utilizing 4-20 mA HART loop protocol communications or cold junction compensation (CJC) reference junctions for temperature loop control, the module maintains electromagnetic immunity and preserves digital data communication stability.
Frequently Asked Questions
Q: Can the S7800A1142 keyboard display module be removed or plugged in while the host relay module is powered?
A: Yes. The module supports hot-plugging directly into the front card slot of an energized 7800 Series relay module without causing interruption to active flame monitoring operations or fault reset sequences.
Q: How far can the S7800A1142 be remote-mounted from the main burner controller module?
A: Remote mounting is supported up to a maximum physical cable length of 1000 feet (305 meters) using a dedicated remote mounting kit with shielded twisted-pair conductors.
Field Installation Guidelines
- Power down primary ac line power to the 7800 Series burner control enclosure if installing an optional flush-mount door frame.
- Align the rear serial connector pins of the S7800A1142 with the front mating header socket on the 7800 Series relay module.
- Press the keyboard display module firmly into place until the top and bottom plastic locking tabs engage securely.
- For remote door-mounting applications, ground the serial cable shield drain wire at the panel functional earth (FE) terminal block only.
- Apply main power to the relay module and verify that the display initializes, showing system status and flame signal strength in millivolts.
