Honeywell Mini-AT, User Manual, Page: 38 / 156

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Page 38
Mini-AT User Guide
Pulse Outputs
As a standard feature, the Mini-AT provides a corrected and uncorrected volume pulse output. The
uncorrected volume pulse is generated from a reed switch mounted on the input switch board as the
magnet disc rotates past switch S3 on each meter revolution. The uncorrected pulse may be wired as
either Form-A (2 wires) or as Form-C (3 wire) at TB1 of the input switch board. The value of each
pulse as determined by the meter type and size. Generally, each pulse represents the amount of uncor-
rected gas flow during a single meter revolution
The corrected volume pulse output is an electronic switch that operates much like an ‘open collector’
transistor. All Mini-AT electronic pulse outputs, including the alarm pulse, incorporate opto-isolators
to electrically isolate the Mini-AT circuitry from the devices receiving the pulses. The volume pulse
output can actually be user configured to output any of the listed pulse types.
• Corrected volume
• Uncorrected volume
• Pressure corrected volume
• Time (Time can only be used with a Form-A output to provide a reset switch at the top of
each hour).
Use Mini-AT Link or MasterLink32 software to select the pulse type at Item Codes 093 and 094. See
pages 43-44 for configuration examples.
The Mini-AT main board can be configured for either Form-A or Form-C volume pulse output. Jumpers at
JB30 and JB31 (see Table 9 on page 73) determine whether a single channel, Form-C pulse output is available
at terminals K, Y and Z of terminal strip TB1; or if two Form-A channels are available at terminals K & Ya and
K & Yb of terminal strip TB1. Additionally, JB29 is used to configure the pulse width for Form-A pulses. For
more information, refer to pages 39-41.
Unless otherwise specified, the Mini-AT is configured for Form-A pulse output. Shorting jumpers are installed
on JB29 to provide a pulse width of 62.5 milliseconds, having a period of 125 milliseconds. Other pulse width
durations are available by moving the shorting jumpers and replacing them with shunt resistors.
Configuring for Form-A volume pulse output