Introduction; Functional Description; Operating Principle - Honeywell Enraf 977 Instruction Manual

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Introduction

1.1 Functional description

The 977 Tank Side Indicator (TSI) is designed to display the level, temperature or other gauge data from the
Honeywell Enraf series 854 servo gauges or the 970/971/973 SmartRadar.
Note:
The Tank Side Indicator can only be connected to the servo gauge if the servo gauge is equipped with the
XPU-2 board with the i.s. option (XPU-2/i.s.).
The Tank Side Indicator can only be connected to the 970 or 971 or 973 SmartRadar if the radar gauge is
equipped with the i.s. output option for 977 TSI (ICU_IS2 board).
The LCD display of the 977 Tank Side Indicator has two 16-characters lines. Incase of the 854 XTG Servo
gauge and 970/971/973 SmartRadar, which have no display, the TSI provides the display function.
The 977 Tank Side Indicator can be installed at ground level or in any other convenient place in the vicinity of
the tank, provided the distance to the level gauge is not more than 250 metres (820 ft).
Only one cable (2 cores) is required for the electrical connection of the 977 TSI. The supply for the 977 TSI is
provided by the level gauge and is intrinsically safe (EEx - ib). The data transmission for the 977 TSI is
superimposed on the supply lines (FSK based on the Bell 202 modem standard).
This manual gives information on:
• Items to be set in the level gauge for the different display functions of the 977 TSI (854 XTG and
970/971/973 SmartRadar only)
• Diagnostic information on the Tank Side indicator and on the level gauges
• Display functions of the 854 ATG / XTG and 970/971/973 SmartRadar

1.2 Operating principle

For firmware version previous A3.0:
The 977 Tank Side Indicator continuously asks the level gauge for items 1A (upper display row display format
A) and 2A (lower display row display format A).
For firmware version A3.0 and higher:
After power up and the initial message, the 977 Tank Side Indicator request for display format (item DF) of the
level gauge. With that information, the 977 TSI continuously asks the level gauge for the selected display format
(upper and lower display row).
The refresh rate is approximately once per second. An "alive" indication is given in the last character on the
upper display row of the Tank Side Indicator by a blinking (on/off) "underscore" (_).
If the communication between the Tank Side Indicator and the level gauge fails for more than 5 or 15 seconds
(the interval time is adjustable), the display information on the 977 TSI is removed and replaced by diagnostic
information about the communication error.
With the optional keyboard consisting of four membrane keys, the different display formats of the level gauge
can be selected and, for servo gauges, gauges commands can be given.
Instruction manual 977 Tank Side Indicator
Introduction
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