Teardown, cleaning and test of a Fluke Helios Plus 2287A Data Acquisition Frontend and 2181A Extender. The Frontend and extender features two Fluke 2280A-161 High Performance A/D Converter 2280A161 cards and nine 20-channel RTD/Resistance Scanner modules, for a total of 180 inputs in this setup with a Frontend and Extender.
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Fluke Helios Plus 2287A
The Fluke Helios Plus Data Acquisition Front End is a data acquisition and control subsystem that can be used with any kind of personal or mainframe computer. The Front End combines a full range of measurement capabilities with easy programmability. It includes RS-232 standard seriel interface. A microcomputer with ROM and RAM to provide local intelligence. Six option slots that accept any of a range of measurement and control modules. Expansion chassis can be added to accommodate more channels in the system.
Fluke Helios Plus manual
CPU and PSU module
The main CPU is a Texas Instruments TMS9995, which essentially is a TI-990 Microcomputer on a single IC.
Analog to Digital converter 2280A-161
Fluke 2280A-161 High Performance A/D Converter 2280A161 has its own smaller microcontroller to respond and time the measurements, in correspondence to the commands from the CPU module. The local controller is a Toshiba TMP80C39AP-6 which is a 8-bit controller running at 6 MHz with 27 I/O and 8 built-in timers.
A Intersil HD3-6402 UART Universal Asynchronous Receiver Transmitter is used for the communication through the mainframe backplane.
RTD/Resistance Scanner 2280A-163
The 20-channel RTD/Resistance Scanner 2280A153 modules only has enough logic ICs to drive the 20 reed relays and communicate with the High Performance ADC 2280A161 card.
Fluke Helios Plus 2287A Serial Interface and Commands
Standard RS-232 interface settings are 9600 baud, 8 bits, even parity and 1 stop bit. <CR> has to be used after commands. The Front End has to be programmed from scratch as it has no memory. To use it with a terminal, we have to tell it for echoing the commands to be human readable.
To make a measurement from all 100 channels, we have to define the (100 Ohm) measurements and read it out.
DEF CHAN(0..99)=RESIST, MAX=100