913MB, 914MB: DC Current/Voltage Modbus-RTU Input Module with Limit Alarms

913MB, 914MB: DC Current/Voltage Modbus-RTU Input Module with Limit Alarms Description

This signal conditioner is a four-channel analog input module with four discrete outputs. It provides isolation between input, output, power, and network circuits.

Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. AC and DC power sources are supported with non-polarized, diode-coupled terminals.

The inputs accommodate wide DC voltage or current ranges. Flexible discrete outputs operate as alarms or on/off controllers. As limit alarms, each discrete output can be configured with high and/or low set-points exclusively tied to an analog input channel. Alarm trips function without host communication enabling low-cost stand-alone alarms, as well as local backup for the primary control system. Otherwise, on/off control is based on commands issued by the host system.

Combining flexible transmitter functions, mixed signal I/O, alarm support, and a network interface in a single package, makes this instrument extremely powerful. Multi-channel design adds cost-efficiency and allows high-density mounting. Plus, safe, rugged construction makes these modules reliable for use in both control room and distributed field I/O applications. Custom module configurations are also possible (consult factory for details).

DC Current, DC Voltage or AC Current Input Limit Alarms or Discrete Outputs

Models:
913MB: 4 current input channels
914MB: 4 voltage input channels
Input Ranges:
0 to 20mA DC
±10V DC
0 to 20A AC (with 5020-350 sensor)
Output:
Four output channels:
Open-drain MOSFETs (1A DC loads)
0 to 35V DC
Network Communication: Modbus-RTU high-speed RS-485
Power Requirement:
10 to 36V DC
24V AC
Approvals:
CE marked. UL, cUL listed
Class I; Division 2; Groups A, B, C, D

Performance Specifications

General Input

Resolution: 0.005% or 1 part in 20,000
Noise Rejection:
Normal mode: 40dB @ 60Hz, typical
Common mode: 140dB @ 60Hz, typical
Input Filter Bandwidth: -3dB at 3Hz, typical
Input Conversion Rate: 180ms per channel

Current Input (913MB)

DC Current Input Ranges: Range user-configured. Range selected applies to all channels.
0 to 1mA, 0 to 20mA, 4 to 20mA
0 to 11.17mA (for use with 5020-350 AC sensor)
DC Current Input Resistance: 49.9 ohms
DC Current Input Accuracy: ±0.1% of input range

Voltage Input (914MB)

DC Voltage Input Ranges: Range user-configured. Range selected applies to all channels.
±10V, ±5V, ±2.5V, ±1.25V,
±625mV, ±313mV, ±156mV, ±78mV
Input Impedance: 110.5K ohms
DC Voltage Input Accuracy: ±0.1% of input range

Discrete Output

Output Type: Four independent open drain MOSFET switches with a common return that operate as low-side switches.
Output Voltage Range: 0 to 35V DC. External voltage source required.
Output Current Range: 0 to 1A DC continuous for each output
Output OFF Leakage Current: 50μA maximum
Output ON Resistance: 0.15 ohms maximum
Output Response Time: 4.1ms typical, from receipt of command to gate transition of the output MOSFET.
Operation: Digital outputs are set to their OFF state following a software or power-on reset. Outputs can optionally be set to user-defined states following a watchdog timeout. Watchdog timeout output control takes precedence over limit alarm control. Alarm control takes precedence over host control.

Communication

Supported Modbus Commands: The command/response protocol for communicating with this module adheres to the Modbus/RTU standard for the following Modbus functions:

• Read Coil (Output) Status
• Read Holding Registers
• Read Input Registers
• Force Single Coil (Output)
• Preset Single Register
• Force Multiple Coils (Output)
• Preset Multiple Registers
• Report Slave ID
• Reset Slave

LED Indicators: LEDs indicate power, status, and discrete level/alarm

Power and Isolation

Power Requirements: 10 to 36V DC or 22 to 26V AC

Supply Current:

Supply      Current Draw
10V DC     125mA maximum
24V DC      50mA maximum
24V AC    100mA rms maximum

Isolation: 
1500V AC for 60 seconds or 250V AC continuous.
4-way isolation between input, network, power, and discrete I/O circuits. Inputs are isolated channel-to channel for common mode voltage to ±4V DC.

Additional information