Emerson FB2100 Flow Computer Instruction Manual
D301783X012
August 2020
Figure 2-47. Connecting a Device to COM2 or COM3 Using RS-485 (2-wire)
2.14
1 RS-485 (2-wire) Port on other device
Regardless of the interface standard (RS-232 or RS-485 2-wire), you must use FBxConnect to configure the port for proper usage.
Security Intrusion Switch
If ordered from the factory, the door contact wires to a momentary switch as shown using cable part number 399331-01-0.
56 Installation
Emerson FB2100 Flow Computer Instruction Manual
D301783X012
August 2020
Figure 2-48. Wiring the Door Contact Terminal to a Momentary Switch
If you order the optional security intrusion switch, the flow computer ships from the factory with the door switch option enabled. To verify this, you can run FBxConnect software and click Services
> Board Info. This allows you to view/modify the enable/disable setting for the Door Switch. Note:
The door switch is always on Module_3.
Figure 2-49. Board Info Screen in FBxConnect
Installation 57
Emerson FB2100 Flow Computer Instruction Manual
D301783X012
August 2020
58 Installation
Emerson FB2100 Flow Computer Instruction Manual
D301783X012
August 2020
Section 3: I/O Configuration and Wiring
This section covers the following topics:
Analog Inputs
Analog Outputs
Digital Inputs
Digital Outputs
Pulse Inputs
Connecting the RTD/PRT
Wiring a Digital Output to the Optional Relay
Radio Wiring
I/O in the FB2100 flow computer comes from the integrated multivariable sensor and RTD connector, and the CPU board with one of possible two I/O options. In I/O option 1 the CPU has a single digital output. In I/O option 2 the CPU has two channels individually configurable as either digital inputs (DI), digital outputs (DO) or pulse inputs (PI) and two channels individually configurable as either analog inputs (AI) or analog outputs (AO).
Note
Terminal blocks TB3 and TB4 are unused on the FB2100.
Note
When using a digital output to drive an inductive load (such as a relay coil), place a suppression diode across the load. This protects the DO from the reverse Electro-Motive Force (EMF) spike generated when the inductive load is switched off.
Notes About Power for an External Device Connected to a Flow Computer I/O Point:
If the external device does not include its own integrated power supply, you must provide your own external supply (30Vdc maximum) for that device.
I/O Configuration and Wiring 59
Emerson FB2100 Flow Computer Instruction Manual
D301783X012
August 2020
Figure 3-1. Base I/O — Option 2 (AI/AO 1&2, DI/DO/PI1&2)
5
6
7
A When wiring a 1-5 V Analog Input (AI), use configuration at left
2
3
B
1
4
When wiring a 4-20 mA Analog Input (AI), use configuration at left
Field Device
Power Supply 30Vdc Max
Open Drain Type or Open Collector Device (Externally Powered)
500 mA load max
To AGND
To AIAOx
Dry contact
60 I/O Configuration and Wiring
