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A-GAGE
MINI-ARRAY
Measuring Light Screen System
5.4.4 Configuring the Scanning Method
The control module may be configured for one of four available scanning methods: straight, interlaced, edge, or skip.
Straight Scan is the default mode in which all beams are scanned in sequence from the bottom end (cable end) to the top end of the
sensors.
Interlaced Scan alternates a straight scan with a slanted-beam scan. A slanted-beam scan begins with a beam established between the
emitter's second channel and the receiver's first channel, and between the emitter's third channel and receiver's second channel,
continuing up the array to the last emitter channel and next-to-last receiver channel. The last emitter channel is then reactivated to
establish a beam to the last receiver channel to complete the scan. Alternating this slanted-beam scan with a straight scan improves
optical resolution within the middle one-third of the scanning range.
Edge Scan activates only the beams located near the top edge of an object in the light screen. "Top edge" refers to the edge of the
object passing nearest the top end of the sensors (i.e., the top of the light screen, farthest from the sensor's cabled end). Each scan
begins six beams prior to the last beam blocked during the previous scan. The scan continues from this point and moves upward to the
first unblocked beam, where the scan is completed. When the array is clear, the system will execute straight scans. Edge Scan begins
again when a blocked channel is detected. This scanning mode is designed to reduce sensing response time when measuring or locating
only one edge of an object. Use of the Edge Scan mode limits the scan analysis mode selection to Last Beam Blocked (LBB).
Skip Scan reduces response time at the expense of decreased sensing resolution. Skip Scan mode allows from one to seven beams to be
skipped during each scan. For example, with one beam skipped, only beams 1, 3, 5, 7, etc. will be interrogated. With two beams
skipped, only 1, 4, 7, 10, etc. will be interrogated, and so on.
Figure 5. Interlaced scan improves optical resolution in the middle one-third of the scanning range.
5.4.5 Configuring the Control Mode
The controller can be configured for Continuous scanning, Gated scanning, or for Host mode. The module offers an optically-isolated
Gate input, which is energized by application of 10 to 30 V dc. Gating is typically accomplished using a dc presence sensing device. Host
mode allows the array to be gated by a host computer or programmable logic controller (PLC).
All MINI-ARRAY Systems can communicate with a host computer or controller via RS-232 serial protocol. In addition, controller models
MAC-1, MACN-1, and MACP-1 also can communicate via RS-485. The host can direct the MINI-ARRAY System to scan on demand and/or
receive the scan data directly from the MINI-ARRAY System in binary or ASCII form. Selectable communication baud rates are 9600,
19200, and 38400.
5.4.6 Configuring the Serial Communication
The MINI-ARRAY System can communicate with its host computer or controller via either RS-232 (all models) or RS-485 (MAC-1,
MACN-1, MACP-1 models) serial protocol. The host can direct the MINI-ARRAY to scan on demand, and/or receive the scan data directly
from the MINI-ARRAY System in Binary or ASCII form.
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