MTL Instruments|8121-DI-DC-01|16-Channel Discrete Input Module
MTL 8121-DI-DC-01 16-Channel Discrete Input Module
Description
MTL 8121-DI-DC-01 is a 16-channel, non-isolated discrete input module powered via bussed 24 V dc, designed for dry contact switches in safe or hazardous areas.
Features
- 16 dry contact inputs
- Module-provided 24 V dc wetting voltage
- Internal common return
- Pulse counting capability
- Non-incendive for hazardous locations
Technical Specifications
- Channels: 16
- Input Type: Dry contact, non-isolated
-
Current Levels:
- OFF Current: < 0.3 mA
- ON Current: > 1.2 mA
- Wetting Current: 2.8 mA (typ.)
-
Pulse Detection:
- Minimum Pulse Width: 5 ms
- Max Frequency (no-debounce): 100 Hz
- Response Time: ≤ 5 ms (field event to Railbus)
-
Isolation:
- Channel to Railbus: 250 V ac
-
Configurable Settings:
- Input Filter: Fast, slow, or user-defined (0–512 ms in 2 ms steps)
- Latch Inputs: Enable/Disable, polarity selectable
- Pulse Counting: Enable/Disable
-
Safety (FM Non-incendive):
- Voc = 30 V, Isc = 3.5 mA
- Ca = 0.12 μF, La = 1000 mH (per channel)
-
Power Requirements:
- Railbus (12 V): 90 mA (typ.), 135 mA (max.)
- Bussed Field Power: 60 mA @ 18–30 V dc
-
Mechanical:
- Module Width: 42 mm
- Weight: 210 g
- Key Code: E1
- Compatible Terminal: 8617-FT-NI
MTL Instruments|8121-DI-DC-01|16-Channel Discrete Input Module

MTL Instruments|8121-DI-DC-01|16-Channel Discrete Input Module
MTL 8121-DI-DC-01 16-Channel Discrete Input Module
Description
MTL 8121-DI-DC-01 is a 16-channel, non-isolated discrete input module powered via bussed 24 V dc, designed for dry contact switches in safe or hazardous areas.
Features
- 16 dry contact inputs
- Module-provided 24 V dc wetting voltage
- Internal common return
- Pulse counting capability
- Non-incendive for hazardous locations
Technical Specifications
- Channels: 16
- Input Type: Dry contact, non-isolated
-
Current Levels:
- OFF Current: < 0.3 mA
- ON Current: > 1.2 mA
- Wetting Current: 2.8 mA (typ.)
-
Pulse Detection:
- Minimum Pulse Width: 5 ms
- Max Frequency (no-debounce): 100 Hz
- Response Time: ≤ 5 ms (field event to Railbus)
-
Isolation:
- Channel to Railbus: 250 V ac
-
Configurable Settings:
- Input Filter: Fast, slow, or user-defined (0–512 ms in 2 ms steps)
- Latch Inputs: Enable/Disable, polarity selectable
- Pulse Counting: Enable/Disable
-
Safety (FM Non-incendive):
- Voc = 30 V, Isc = 3.5 mA
- Ca = 0.12 μF, La = 1000 mH (per channel)
-
Power Requirements:
- Railbus (12 V): 90 mA (typ.), 135 mA (max.)
- Bussed Field Power: 60 mA @ 18–30 V dc
-
Mechanical:
- Module Width: 42 mm
- Weight: 210 g
- Key Code: E1
- Compatible Terminal: 8617-FT-NI